240vac capacitor type?

[cjdelphi]

I have the image but not where i found it (google image search)

I'm not sure what kind of cap should be used on the 240ac out... (the low dc side/circuit works)

Film type? Electrolytic? Ceramic?

Suggestions? Thanks!

 

[Minder]

Ceramic, oil filled paper AC rated, definitely not electrolytic.
M.

 

[rickselectricalprojects]

you should use a mkp safety cap like these ones: http://au.mouser.com/ProductDetail/...GAEpiMZZMukHu%2bjC5l7Yc8vu77rhzt2W4yNejHobOg=

 

[cjdelphi]

That cleared that up! Thanks

 

[Colin Mitchell]

Are you aware the 2u2 will absorb something like 100mA @200v and do nothing for the quality of the output. It is just a worthless circuit that has never been tested.

 

[Old Steve]

Are you aware the 2u2 will absorb something like 100mA @200v and do nothing for the quality of the output. It is just a worthless circuit that has never been tested.

^ What he said - I get 160mA at 230VAC 50Hz. (Xc=1447 ohms) Edit: That works out at 37W load before you even connect anything.

Even worse at higher frequencies.

 

[cjdelphi]

Curiosity..... building a 555 version on the breadboard now

 

[Old Steve]

Curiosity..... building a 555 version on the breadboard now

So how did you go?
I assume you did it without the caps?

 

[cjdelphi]

Yeah removed the caps got the timing frequency from the switch rate of the fet not what appeared from the transformer...

Being custom built i got a nice 240vac out but the ac frequency was more like 200hz and the timing frequencies could not be adjusted low enough..

But the 555 was causing me issues with 11v still working on that

 

[Old Steve]

Yeah removed the caps got the timing frequency from the switch rate of the fet not what appeared from the transformer...

Being custom built i got a nice 240vac out but the ac frequency was more like 200hz and the timing frequencies could not be adjusted low enough..

But the 555 was causing me issues with 11v still working on that

I was wondering how you went.

Keep that frequency as close to 50Hz as possible, or the iron transformer core will start to heat up unacceptably with higher frequencies.

How does it perform for output voltage under a (very light) load? Tried yet?
Don't load it too heavily or you'll easily exceed the 1.5A current rating of the transformer's (original) primary.

I tried this many years ago but quickly realised it wasn't really suitable for any practical purpose, especially with square-wave input, but a good little experiment all the same.